ten tons. small by nasa standards. >> it is very hard to see. those are only observable in a few days of earth. this one actually slipped by our notice and came into the atmosphere. >> others are under a microscope so to speak. >> nasa monitors 9,000 asteroids and the big ones, a thousand of those, we monitor quite carefully. we call those potentially hazardous objects and look at their orbits and there are many hundreds before we have to worry about close approaches by those objects. >> that is good news. not as good for russia today. the president has ordered aid to be sent to the area and schools are closed because it is zero and the windows are broken. >> right now, nasa is watching for another event unrelated to the meteor, a giant 150' asteroid will fly by earth in the next half hour. observatories around the earth are pointing telescopes in the direction of the asteroid. amy joins us live from the laboratory in oakland where there is a party going on. amy? >> the party will be tonight when we can see it, closest to the earth in the next half hour but we cannot see it. it is so